US3768385A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for producing a master dot pattern for photo-etching of a graded hole shadow mask
Assignee: Toppan Inc
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Filing: 1971-07-02
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Granted: 1973-10-30
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Expires: 1991-07-02
Abstract
Abstract Apparatus for the production of master dot patterns for photoetching a graded-hole shadow mask for use in a color picture tube comprising mounting a grading mask having its transparency concentrically, progressively decreasing from the center toward the periphery thereof between a light source and a photographic material and inserting a screen between the grading mask and the light source.
Inventors
- 👤 K Noguchi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 03:34
CPC Classifications
H; H01; H01J; H01J9/00; H01J9/20; H01J9/22; H01J9/227; H01J9/2271; H01J9/2272; H01J9/2273
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
134 words
Apparatus for the production of a master dot pattern for photo-etching of graded hole shadow masks in color television picture tubes comprising a light source, a photographic material spaced from said light source and adapted to be formed as said master dot pattern, a screen with a regular arrangement of openings therein positioned between said light source and said photographic material, a grading mask adjacent said screen and between said source and photographic material, said grading mask comprising a flat plate of photographic material having a progressively decreasing transparency from the center thereof to its periphery to control the exposure intensity in the central and peripheral portions of the master dot pattern without substantial deflection of the light rays from said light source and a lens and diaphragm between said mask and said screen.
Claim 2
Dependent Claim
134 words
Apparatus for the production of a master dot pattern for photo-etching of graded hole shadow masks in color television picture tubes comprising a light source, a photographic material spaced from said light source and adapted to be formed as said master dot pattern, a screen with a regular arrangement of openings therein positioned between said light source and said photographic material, a grading mask adjacent said screen and between said source and photographic material, said grading mask comprising a flat plate of photographic material having a progressively decreasing transparency from the center thereof to its periphery to control the exposure intensity in the central and peripheral portions of the master dot pattern without substantial deflection of the light rays from said light source and a lens and diaphragm between said mask and said screen.
Claim 3
Dependent Claim
28 words
Apparatus as claimed in claim 1 wherein said plate has a light transmittance characteristic arranged in concentric circular fashion, the transmittance decreasing from the center to the periphery.
Claim 4
Dependent Claim
29 words
Apparatus as claimed in claim 2 wherein said plate comprises a succession of stacked elements having uniform light transmittance and provided with concentric openings which successively increase in diameter.
Claim 5
Dependent Claim
23 words
Apparatus as claimed in claim 2 wherein said plate is semitransparent and has uniform light transmittance, said plate hAving a conical recess therein.
Claim 6
Dependent Claim
43 words
Apparatus as claimed in claim 1 comprising a circular disc having a transparent portion and an opaque portion, and comprising means to provide relative rotation between said disc and said flat plate of photographic material, said transparent portion providing said progressively decreasing transparency.
Claim 7
Dependent Claim
39 words
Apparatus as claimed in claim 5 wherein said transparent portion has one radial edge and one curved edge intersecting at the center of the disc, the curved edge being progressively further from the radial edge with increasing radial distance.
Claim 8
Dependent Claim
31 words
Apparatus as claimed in claim 5 wherein said transparent portion is an angular sector, and comprising an optical wedge in said transparent portion with a density varying radially in said wedge.
Claim 9
Dependent Claim
57 words
Apparatus as claimed in claim 1 comprising a printing frame, said light source being within said frame, a glass member on said frame, said screen being mounted on said glass member, said photographic material having an emulsified surface and being mounted on said screen, said mask being in said frame between said source and said glass member.
Claim 10
Dependent Claim
25 words
Apparatus as claimed in claim 8 comprising a diffusing plate supporting said grading mask and adjustable in distance relative to said source and glass member.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-10-29 | 1977-04-30 | 1977-10-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-29 | 1981-04-30 | 1981-10-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-29 | 1985-04-30 | 1985-10-30 | $7700.00 | Window Closed / Lapsed |